Review the added add-ons and the removed add-ons (if any) then tap Continue.

From the "Congratulations! you now have Advanced Calling" section, tap OK. Restart the device in 5 minutes to complete activation. Check for incompatible add-ons that must be removed in order for HD Voice to be activated.

The voice portion of the call is billed per minute of use and the video portion is billed as data. For additional info, see these HD Voice FAQs.